How do you allow for minor length variation to the plans?

Fast Trim orders for Skirting Board are supplied scribed on left-hand end with square-cut on right-hand end unless otherwise noted. They are supplied 50mm over the length on the right-hand end allowing for minor variations to the takeoffs. You cut this end to length on site.

For Architraves, we determine and supply the required number of pieces of mitred architrave with a mitre to right end and the length, the required number of pieces with a mitre to left end and the length and the number of pieces with mitres to both ends and length.